Tetrahydropentalene

Abstract

Das ous Cyctooctatetraen zugHnglche 1.2-Dihydrapentalea (9) kanm mit Li-m l,2,314-Tetrahydropental~ (2) und 1,2,3$-Tet.rahy&opentakn (3) redudert werden. Zur praparativen Herstellung arbeitet man fiir 2 bei kktischer KoatroUe, ffir 3 bei t h e m -Kontrone. D i e vergleichbare Addition von zm-Butyltithium fihrt zu den substituierten Tetrahydropentale-~m

Thermal Stereomutations and Vinylcyclopropane-to- Cyclopentene Rearrangement of 2-Methylene-3-spiro- cyclopropanebicyclo[2.2.1]heptane

“…2-Methylene-3-spirocyclopropanebicyclo[2.2.1]heptane ( 4 ) was selected as a suitable substrate to test this inference. Thermal isomerization of 4 would be expected to give tricyclo[5.2.1.0 2,6 ]-dec-2(6)-ene ( 5 ) as a reactive intermediate, which through a retro Diels−Alder reaction would provide the known tetrahydropentalenes 6 and 7 . The geometrically limited vinylcyclopropane 4 was readily prepared from 3-methylenenorbornanone, through Simmons-Smith and then Wittig reactions.…”